 /*******************************************************************************
  * Copyright (c) 2004, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.intro;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.ui.IPluginContribution;
 import org.eclipse.ui.internal.registry.IWorkbenchRegistryConstants;
 import org.eclipse.ui.intro.IIntroPart;
 import org.eclipse.ui.intro.IntroContentDetector;
 import org.eclipse.ui.plugin.AbstractUIPlugin;

 /**
  * Describes an introduction extension.
  *
  * @since 3.0
  */
 public class IntroDescriptor implements IIntroDescriptor, IPluginContribution {


     private IConfigurationElement element;

     private ImageDescriptor imageDescriptor;

     /**
      * Create a new IntroDescriptor for an extension.
      */
     public IntroDescriptor(IConfigurationElement configElement)
             throws CoreException {
         element = configElement;

         if (configElement.getAttribute(IWorkbenchRegistryConstants.ATT_CLASS) == null) {
             throw new CoreException(new Status(IStatus.ERROR, configElement
                     .getNamespace(), 0,
                     "Invalid extension (Missing class name): " + getId(), //$NON-NLS-1$
 null));
         }
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.intro.IIntroDescriptor#createIntro()
      */
     public IIntroPart createIntro() throws CoreException {
         return (IIntroPart) element.createExecutableExtension(IWorkbenchRegistryConstants.ATT_CLASS);
     }
     
     public IntroContentDetector getIntroContentDetector() throws CoreException {
         if (element.getAttribute(IWorkbenchRegistryConstants.ATT_CONTENT_DETECTOR) == null) {
             return null;
         }
         return (IntroContentDetector) element.createExecutableExtension(IWorkbenchRegistryConstants.ATT_CONTENT_DETECTOR);
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IIntroDescriptor#getId()
      */
     public String getId() {
         return element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IIntroDescriptor#getImageDescriptor()
      */
     public ImageDescriptor getImageDescriptor() {
         if (imageDescriptor != null) {
             return imageDescriptor;
         }
         String iconName = element.getAttribute(IWorkbenchRegistryConstants.ATT_ICON);
         if (iconName == null) {
             return null;
         }
         
         imageDescriptor = AbstractUIPlugin.imageDescriptorFromPlugin(element
                 .getNamespace(), iconName);
         return imageDescriptor;
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPluginContribution#getLocalId()
      */
     public String getLocalId() {
         return element.getAttribute(IWorkbenchRegistryConstants.ATT_ID);
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPluginContribution#getPluginId()
      */
     public String getPluginId() {
         return element.getNamespace();
     }
     
     /**
      * Returns the configuration element.
      *
      * @return the configuration element
      * @since 3.1
      */
     public IConfigurationElement getConfigurationElement() {
         return element;
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.intro.IIntroDescriptor#getLabelOverride()
      */
     public String getLabelOverride() {
         return element.getAttribute(IWorkbenchRegistryConstants.ATT_LABEL);
     }
 }

